Semiconductor Light Extraction Surface Cone Array
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Solution Overview
Problem
The external quantum efficiency of deep ultraviolet light output from semiconductor light emitting devices is low, particularly due to the low light extraction efficiency from the substrate's light extraction surface, with shorter wavelengths experiencing even lower efficiencies.
Innovation Solution
A semiconductor light emitting device with a light extraction layer featuring an array of cone-shaped parts on its surface, where the cone-shaped parts occupy between 65% to 95% of the area and have an aspect ratio of 0.3 to 1.0, with a first portion having a hexagonal shape and a second portion closer to the apex with a smaller angle of inclination, enhancing light extraction by reducing total reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the proportion of area occupied by cone-shaped parts is increased to improve light extraction efficiency, then light extraction efficiency is improved, but manufacturing difficulty increases
Solution Approach 1:
The patent optimizes specific parameters of the cone-shaped parts including aspect ratio (0.5-1.5), area proportion (65-95%), and base shape (hexagon or circle) to achieve high light extraction efficiency while maintaining manufacturability through controlled parameter ranges
2Loss of energy
If the aspect ratio of cone-shaped parts is increased to improve light extraction efficiency, then light extraction efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent defines a specific aspect ratio range (0.5-1.5) that balances light extraction performance with manufacturing feasibility, avoiding excessively high aspect ratios that would be difficult to manufacture while still achieving significant efficiency improvement
3Loss of energy
If the area proportion of cone-shaped parts is increased to improve light extraction efficiency, then light extraction efficiency is improved, but device complexity increases
Solution Approach 1:
The patent uses cone-shaped parts with curved surfaces (circular or hexagonal bases) instead of flat surfaces, creating a periodic concave-convex structure that effectively reduces total internal reflection while maintaining relatively simple manufacturing processes
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration significantly improves the light extraction efficiency of deep ultraviolet light emitting devices by optimizing the area coverage and aspect ratio of cone-shaped parts on the light extraction surface, leading to higher light output and external quantum efficiency.
Implementation Method 1
the concave-convex structure provided by forming multiple cone-shaped parts in an array on the light extraction surface inhibits total reflection of light occurring inside the light extraction surface
Data Source
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AI summary
A semiconductor light emitting device 10 includes a light extraction layer having a light extraction surface 22b. Multiple cone-shaped parts 52 formed in an array is provided on the light extraction surface 22b of the semiconductor light emitting device 10. A proportion of an area occupied by the multiple cone-shaped parts 52 per a unit area of the light extraction surface 22b is not less than 65% and not more than 95% in a plan view of the light extraction surface 22b, and an aspect ratio h/p defined as a proportion of a height h of the cone-shaped part 52 relative to a distance p between apexes of adjacent cone-shaped parts 52 is not less than 0.3 and not more than 1.0.